Distal Tibia: Is It The Best Source For Bone Graft?
Numerous primary and revisional surgical procedures mandate using either osseous autografts or allografts. Although allografts continue to increase in popularity, most podiatric surgeons will agree that autografts offer distinct advantages in healing and are preferable when possible. In comparison to autogenous grafts, allografts help facilitate an absence of donor site morbidity, unlimited supply and decreased surgical time. However, autografts provide numerous benefits such as host compatibility, viable precursor cells and superior immunologic properties.1,2
As with any surgical procedure, you must weigh the pros and cons of choosing auto- or allograft. You must also evaluate the patient and procedure in order to choose the appropriate site for graft harvesting. With this in mind, perhaps it’s time to consider (or reconsider) the distal medial tibia as a viable source for autogenous bone.
Indications or operative opportunities to employ autografts include delayed unions, non-unions, arthrodesis enhancement, tumors, repositional osteotomies and lengthenings. These are the more common indications for using an autograft. Post-traumatic reconstruction and reconstruction following osteomyelitis are two additional indications.
Reviewing The Pros And Cons Of Potential Donor Sites
In more than a century of formal autografting, researchers have advocated numerous harvest sites. Meador and Eggers provide a thorough manuscript illustrating the full history of auotgenous grafting.3
The illiac crest can give you a very large section of cancellous or corticocancellous bone. Depending upon the harvesting technique, surgeons may obtain one, two or three-sided grafts. Although the illiac crest is an excellent source for graft material, be aware that researchers have reported significant blood loss.4 Anecdotally, it has been my experience that this particular harvest site can be a significant source of post-operative pain when compared with podiatric donor sites.
Naturally, this also has the added inconvenience of having to have an alternative surgeon obtain the graft. Even though this graft is obtained from a relatively large osseous structure, keep in mind that complications, such as stress and complete fractures, are still possible.
The calcaneus is an excellent source of both cancellous and relatively small amounts of cortical bone.5 Depending on the position and size of the lateral incision(s), you can obtain various shapes and sizes of grafts. Make sure you avoid the sural nerve and also be extra cautious medially as there is a higher possibility of neurovascular injury or fibrous of the tarsal tunnel. As with any graft site, it is essential to take the appropriate precautions in order to avoid possible fracture following harvesting.
Primarily, the fibula provides a large cortical strut for operative procedures.6 Small portions of cancellous bone are available in the more distal aspects of the fibula. Your primary concern with this type of graft is not disrupting the ankle joint.7 This can occur if you inadverently enter the ankle joint or via aggressive resection of the fibula.
The proximal or distal tibia is a good source of fairly large quantities of corticocancellous bone. I harvest most autografts from the distal medial tibia for the following reasons: Ease of surgical access (few vital structures to avoid); minimal postoperative pain; low complication rate; and the choice of cortical or cancellous bone. Often, the medial column of the foot is the surgical site and due to external rotation of the limb, you’ll find the medial ankle more accessible than the lateral calcaneus.